Systems that are used to show information in the form of advertisements, timetable messages or arrival and departure times in present-day public service infrastructures with regard to buses, trains, subway traffic, etc., is  are of a static nature. Such information is given on notice boards, posters, charts, tables, verbally through loudspeakers, and on digital displays, etc. A characteristic feature of such information media is that the information media is not coordinated, but is in the form of individual items which are controlled and updated separately, often manually.
Modem  Modern digital displays used, e.g., in conjunction with subway railway traffic gives  give some of the aforesaid information but is  are not controlled to display advertisements, warning messages, etc. Furthermore, the information is often supplemented with verbal messages transmitted from traffic control centres. The information channel cannot be subscribed to directly for the display of external information suppliers, such as advertising bureaux, the authorities, newspapers, etc., but is processed administratively and fed manually into the information display systems.
Although the administration of information is often processed manually with the aid of modern computer technology, the available display time will nevertheless contain “dead time”, among other things due to back-logging caused by the manual infeed process.
Thus, present-day systems do not enable information to be updated dynamically for display in real time. Neither do present-day systems enable external mediators to update information for display in a central control system, nor yet the administrator who makes the display of information available, but that  it is the administrator who determines when, where and how the information shall be displayed.
The present-day static information display systems are therefore beset with a number of problems.
Also known to the art are systems for displaying or showing picture series in local public places, such as assembly halls, lecture halls, and conference rooms in industry. The systems comprise diapositive projectors which are controlled to display pictures, images and sound in an attractive manner, often with rapid picture changes and overlaps, so as to avoid the risk of boring viewers, as with conventional display with diapositive projectors. The computer control of such systems may well be both complicated and advanced. Unfortunately, these systems are nevertheless static insofar as they are used in one and the same locality and controlled and managed on the display site. The display must be planned carefully beforehand, this planning often being carried out by experts within the technical field in question, so as to obtain a finished display product. For instance, when a company wishes to change its display and introduce a new picture series combined with sound, the process again becomes static by virtue of the need to employ experts to program and arrange the new display.
The same problem as that mentioned above is also met when showing pictures through diapositive projectors in one and the same locality, because the display subscriber has very little chance of influencing the display, especially in real time. The picture display is directed towards a limited public and towards scheduled display of one and the same information material to the public concerned. The picture display is not directed to a large number of people, as in the case of a railway station platform, a subway platform or in airports. In places of this nature, it should be possible to spread the information and to display different information in different places within said stations and it should be possible to update and change the information quickly. When the information displayed on said station is not effectively coordinated, the displays on which information is presented will often become static, for instance show the time of the next display or show a pause picture, i.g. dead time. This becomes nerve-wracking to travellers, who often wait for long periods in waiting halls or stand on platforms. Neither is the failure to utilize expensive information display equipment to the highest possible degree compatible with good economy.